Oxygen scavenging molecules, articles containing same, and methods of their use

ABSTRACT

The invention relates to compounds of the structure of formula I and II: 
                         
where X is selected from the group consisting of O, S and NH; Y, A and B are independently selected from the group consisting of N and CH; D, E and F are independently selected from the group consisting of CH, N, O and S; the symbol — represents a single or a double bond; and R 1 , R 2  and R 3  are independently selected from the group consisting of H, electron withdrawing groups and electron releasing groups. In other embodiments, the compounds are used as oxygen scavengers and in barrier compositions and articles.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/928,553, filed May 10, 2007, the entirety of which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to compounds useful for oxygen scavenging.The invention also relates to substantially transparent compositionsthat comprise a base polymer, an oxidizable organic component, and atransition metal. The invention also is directed to uses of suchcompositions in the construction of packaging for oxygen sensitivematerials.

BACKGROUND OF THE INVENTION

It is known in the art to include an oxygen scavenger in the packagingstructure for the protection of oxygen sensitive materials. Suchscavengers are believed to react with oxygen that is trapped in thepackage or that permeates from outside of the package, thus extending tolife of package contents. These packages include films, bottles,containers, and the like. Food, beverages (such as beer and fruitjuices), cosmetics, medicines, and the like are particularly sensitiveto oxygen exposure and require high barrier properties to oxygen topreserve the freshness of the package contents and avoid changes inflavor, texture and color.

Use of certain polyamides in combination with a transition metal isknown to be useful as the oxygen scavenging material. One particularlyuseful polyamide is MXD6 which contains meta-xylene residues in thepolymer chain. See, for example, U.S. Pat. Nos. 5,639,815; 5,049,624;and 5,021,515.

Other oxygen scavengers include potassium sulfite (U.S. Pat. No.4,536,409), unsaturated hydrocarbons (U.S. Pat. No. 5,211,875), andascorbic acid derivatives (U.S. Pat. No. 5,075,362).

In barrier layers of packaging walls that are made from blends of oxygenscavenging materials with base polymer resins such as PET, haze canresult due to such factors as the immiscibility of the scavengingmaterials with the base polymer resins and the inability to create bymechanical blending means disperse-phase domains that are so small asnot to interfere with the passage of light therethrough; and the adverseinfluence of the scavenging material on the crystallization behavior ofPET base resin. One approach to minimizing such haze is carefulselection of base resin to improve dispersibility of the scavengermaterial and, thus, reduce, but not substantially eliminate, haze; andto minimize the adverse crystallization effect. This approach mayundesirably narrowly restrict the choice of base polymer resin. Anotherapproach is to use compositions that serve as compatibilizers to reducehaze. These approaches add cost to the layer and the compatibilizer addsan additional material that must be evaluated for its suitability forcontact with food. Thus, there is a need in the art for improvedmaterials which provide high oxygen scavenging capability and aresubstantially transparent.

SUMMARY OF THE INVENTION

The present invention is directed to compositions comprising:

-   -   (a) a base polymer;    -   (b) at least one compound of Formula I or II

wherein X is selected from the group consisting of O, S and NH; Y, A andB are independently selected from the group consisting of N and CH; D, Eand F are independently selected from the group consisting of CH, N, Oand S; the symbol—when used in conjunction with a bond line represents asingle or a double bond; and R₁, R₂ and R₃ are independently selectedfrom the group consisting of H, electron withdrawing groups and electronreleasing groups and a transition metal; and (c) at least one transitionmetal in a positive oxidation state, said metal being present in thecomposition in an amount of 10 to 400 ppm; wherein said compound ispresent in an amount of about 0.10 to 10 weight percent of saidcomposition. Methods of preparing, as well as methods of implementing,the compositions of the present invention are also described.

Also within the scope of the present invention are compounds of FormulasI and II. Methods of preparing and using the compounds of Formulas I andII are also described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the percent oxygen in a vial containing MXBP, a preferredembodiment of the present invention, over 18 days.

FIG. 2 shows that PET based plaques made with MXBP, preferredembodiments of the present invention, scavenge approximately 14% ofoxygen in an enclosed environment after 25 days.

FIG. 3 Oxygen scavenging data for Compound 306, a preferred embodimentof the present invention. ▪=QC (reference sample comprising 1.5% MXD6,2% cobalt masterbatch (cobalt neodecanoate in PET); ▴=2% Compound 306+2%Cobalt Masterbatch+Vitiva; ♦=air.

FIG. 4 Oxygen scavenging data for Compound 310, a preferred embodimentof the present invention. ▪=QC (reference sample comprising 1.5% MXD6,2% cobalt masterbatch (cobalt neodecanoate in PET); ▴=2.5% Compound310+2% Cobalt Masterbatch +Vitiva; ♦=air.

FIG. 5 Oxygen scavenging data for Compound 307, a preferred embodimentof the present invention. ▪=QC (reference sample comprising 1.5% MXD6,2% cobalt masterbatch (cobalt neodecanoate in PET); ▴=4% Compound 307+2%Cobalt Masterbatch+Vitiva; ♦=air.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In some embodiments, the invention concerns compounds of Formula I andII:

wherein X is selected from the group consisting of O, S and NH; Y, A andB are independently selected from the group consisting of N and CH; D, Eand F are independently selected from the group consisting of CH, N, Oand S; the symbol—represents a single or a double bond; and R₁, R₂ andR₃ are independently selected from the group consisting of H, electronwithdrawing groups and electron releasing groups.

In some aspects, the invention concerns compounds having the formula:

wherein X is O, S or NH; Y, A and B are independently N or CH; D, E andF are independently CH, N, O or S; the symbol—in addition to the solidline represents a single or a double bond; and R₁, R₂ and R₃ areindependently H, electron withdrawing groups or electron releasinggroups.

In some compositions, X is O; Y, A and B are all CH; D, E, and F are allCH;—is a double bond; and R₁, R₂ and R₃ are all hydrogen. Certaincompositions have the formula

Other compositions have the formula

In other preferred embodiments, X is O; Y is N, A and B are CH; D, E,and F are all CH;—is a double bond; and R₁, R₂ and R₃ are all hydrogen.Certain compositions of the present invention have the formula:

In yet other embodiments R₁ and R₃ are electron releasing groups.Electron releasing groups, also known as electron donating groups, areknown in the art. Preferred electron releasing groups include branchedand straight chain alkyl groups, for example, methyl, ethyl, propyl,isopropyl, butyl, isobutyl, and tert-butyl. Certain preferredcompositions of the present invention have the formula:

Other preferred electron releasing groups include alkoxy, for examplemethoxy and ethoxy. Still other preferred electron releasing groupsinclude amines, for example —NH₂ and N(loweralkyl)₂.

In still other embodiments, R₁ and R₃ are electron withdrawing groups.Electron withdrawing groups are known in the art. Preferred electronwithdrawing groups include nitro, carboxylic acid, esters, for exampleloweralkyl esters, and cyano. Certain preferred compositions of thepresent invention have the formula:

Other preferred compositions of the present invention have the formula:

Yet other compositions of the present invention are of the formula:

wherein X is O, S or NH; Y, A and B are independently N or CH; D, E andF are independently CH, N, O or S; the symbol—in addition to the solidline represents a single or a double bond; and R₁, R₂ and R₃ areindependently H, electron withdrawing groups or electron releasinggroups. In certain of these compositions, X is O; Y, A and B are all CH;D, E, and F are all CH;—is a double bond; and R₁, R₂ and R₃ are allhydrogen.

Other compositions of the invention have the formula

In some aspects, the invention concerns organic material normallysusceptible to gradual degradation in the presence of oxygen during useover an extended period containing an antioxidant, or oxygen scavenging,effective amount of a compound disclosed herein.

Some aspects of the invention concern containers comprising afilm-forming polymer, having at least one wall comprising an effectiveamount of an oxygen-scavenging composition comprising a compounddisclosed herein.

Other aspects concern oxygen scavenging compositions that react withoxygen in the presence of transition metals and salts thereof comprisingan effective amount of a compound disclosed herein. The invention alsorelates to an oxygen scavenging system comprising: (a) an oxygenscavenging composition comprising a compound of Formula I or II; (b) aneffective amount of a transition metal catalyst; and (b) a functionalbarrier permeable to oxygen.

The invention also relates to compositions comprising (a) a basepolymer; (b) at least one compound of Formula I or II; and (c) at leastone transition metal in a positive oxidation state, the metal beingpresent in the composition in an amount of 10 to 400 ppm; where thecompound is present in an amount of about 0.10 to 10 weight percent ofthe composition. One preferred transition metal is cobalt. In someembodiments, the at least one transition metal further comprises zinc.In other embodiments, the transition metal comprises zinc and cobalt.

In some compositions, the base polymer comprises a polyester polymer.One preferred polyester polymer is polyethylene terephthalate.

The compound(s) described herein is present in an amount of about 1 toabout 10 weight percent based on the weight of the composition in someembodiments. In other embodiments, the oxygen scavenging compound ispresent in an amount of about 1 to about 5 weight percent based on theweight of the composition. In still other embodiments, the compound ispresent in an amount of about 1 to about 3 weight percent based on theweight of the composition. Also within the scope of the invention arethose embodiments were the compound(s) described herein is present in anamount of about 0.1 to about 10 weight percent based on the weight ofthe composition.

Some preferred embodiments of the invention have a concentration oftransition metal from 30 to 150 ppm of the total composition weight.

Other aspects of the invention concern package walls comprising at leastone layer, the layer comprising a composition, the compositioncomprising: (a) a base polymer; (b) at least one compound of Formula Ior II; and (c) at least one transition metal in a positive oxidationstate, the metal being present in the composition in an amount of 10 to400 ppm; wherein the compound is present in an amount of about 0.10 to10 weight percent of the composition.

Yet other aspects of the invention relate to package walls comprising acomposition, the composition comprising: (a) one or more outer layers;and (b) one or more inner layers; wherein at least one of the inner orat least one of the outer layers comprises a composition comprising: (1)a base polymer; (2) at least one compound of formula I or II; and (3) atleast one transition metal in a positive oxidation state, the metalbeing present in the composition in an amount of 10 to 400 ppm; whereinthe compound is present in an amount of about 0.10 to 10 weight percentof the composition. In some embodiments, the first layer is disposedradially outward from the second layer.

The invention also relates to methods for packaging an oxygen sensitivematerial comprising:

-   -   (a) preparing a package having a wall comprising at least one        layer, at least one of the layers comprising a composition, the        composition comprising        -   a base polymer;        -   at least one compound of Formula I or II; and        -   at least one transition metal in a positive oxidation state,            the metal being present in the composition in an amount of            10 to 400 ppm; wherein the compound is present in an amount            of about 0.10 to 10 weight percent of the composition;    -   (b) introducing the oxygen sensitive material into the package;        and    -   (c) closing the package.

Still other embodiments of the invention concern methods for producing apackaging material having a wall with oxygen barrier propertiescomprising:

-   -   (a) combining a base polymer with at least one compound of        formula I or II to form a composition, the composition having at        least one transition metal in a positive oxidation state, the        metal being present in the composition in an amount of 10 to 400        ppm; and wherein the compound is present in an amount of about        0.10 to 10 weight present of the composition;    -   (b) forming the product of step (a) into a wall; and    -   (c) forming a container which comprises the wall.

Another aspect of the invention concerns processes for making an articlecomprising:

-   -   (a) forming a melt by combining in a melt processing zone:        -   a base polymer,        -   at least one compound of formula I or II, and        -   at least one transition metal in a positive oxidation state,            the metal being present in the composition in an amount of            10 to 400 ppm; wherein the compound is present in an amount            of about 0.10 to 10 weight present of the composition;    -   (b) forming an article from the melt.

In some embodiments, the article is a perform, a sheet, a bottle, a cup,or a jar.

The terms “electron-withdrawing” or “electron-donating” refer to theability of a substituent to withdraw or donate electrons relative tothat of hydrogen if hydrogen occupied the same position in the molecule.These terms are well-understood by one skilled in the art and arediscussed, for example, in Advanced Organic Chemistry by J. March, 1985,pp. 16-18.

Electron withdrawing groups include fluoro, chloro, bromo, nitro, acyl,cyano, carboxyl, lower alkenyl, lower alkynyl, carboxaldehyde,carboxyamido, aryl, quaternary ammonium, trifluoro-methyl,alkoxycarbonyl, aryloxycarbonyl, aminocarbonyl, sulfonic,alkanesulfonyl, arylsulfonyl, perfluoroalkanesulfonyl,perfluoroarylsulfonyl, phosphoryl, tertiary amine cation and acombination thereof among others.

Electron donating groups include such groups as hydroxy, lower alkoxy,lower alkyl, amino, lower alkylamino, di(lower alkyl)amino, aryloxy,mercapto, lower alkylthio, lower alkylmercapto and disulfide amongothers. One skilled in the art will appreciate that the aforesaidsubstituents may have electron donating or electron withdrawingproperties under different chemical conditions. Moreover, the presentinvention contemplates any combination of substituents selected from theabove-identified groups.

In some embodiments, the most preferred electron donating or electronwithdrawing substituents are halo, nitro, alkanoyl, carboxaldehyde,arylalkanoyl, aryloxy, carboxyl, carboxamide, cyano, sulfonyl,sulfoxide, heterocyclyl, guanidine, quaternary ammonium, lower alkenyl,lower alkynyl, sulfonium salts, hydroxy, lower alkoxy, lower alkyl,amino, lower alkylamino, di(lower alkylamino), amine lower mercapto,mercaptoalkyl, alkylthio and alkyldithio.

The antioxidant/oxygen scavenger of the invention can be used in a broadrange of organic products normally subject to gradual degradation in thepresence of oxygen during use over an extended period. In someembodiments, the organic compositions protected by the presentantioxidants are of the type in which the art recognizes the need forantioxidant protection and to which an antioxidant of some type iscustomarily added to obtain an extended service life. The oxidativedegradation protected against is the slow gradual deterioration of theorganic composition rather than, for example, combustion. In otherwords, the present additives are not necessarily flame retardingadditives nor flame suppressing.

In some embodiments, the antioxidant/oxygen scavenger can be utilized atelevated temperatures. One such use would be during a melt processingoperation.

In some embodiments, the invention relates to synthesis of the compoundsof the invention. In a first synthetic scheme about 2 moles of acompound of the formula

is reacted under reaction conditions to release water, which is trappedin a Dean-Stark trap, with one mole of a compound of the formula

to produce the desired product having the formula:

wherein all the groups are as defined above.

In one preferred embodiment, 2 moles of phthalide (also known aso-hydroxymethyl-benzoic acid lactone or 1,3-dihydrobenzo[c]furan-1-oneor oxophthalane or 1(3H)-isobenzo-furanone) are reacted withmeta-xylylenediamine as shown below:

In another synthetic embodiment, phthalic anhydride is reacted withmetaxylylene diamine to produce the diimide product and then as shownbelow:

Further embodiments of the present invention can be prepared usingmethods known generally in the art in accordance with the followingSchemes:

Even further embodiments can be prepared according to the Schemes below:

Modifications known in the art can be used to produce furtherembodiments of the present invention.

Examples of organic materials in which the additives are useful includepolymers, both homopolymers and copolymers, of olefinically unsaturatedmonomers, for example, polyolefins such as polyethylene, polypropylene,polybutadiene, and the like. Also, poly-halohydrocarbons such aspolyvinyl chloride, polychloroprene, polyvinylidene chloride, polyfluoroolefins, and the like, are afforded stabilization. The additives provideantioxidant protection in natural and synthetic rubbers such ascopolymers of olefinically unsaturated monomers includingstyrene-butadiene rubber (SBR rubber), ethylenepropylene copolymers,ethylene-propylenediene terpolymers such as the terpolymer of ethylene,propylene and cyclopentadiene or 1,4-cyclooctadiene. Polybutadienerubbers such as cis-polybutadiene rubber are protected.Poly-2-chloro-1,3-butadiene (neoprene) and poly-2-methyl-1,3-butadiene(isoprene rubber) are stabilized by the present additives. Likewise,acrylonitrile-butadiene-styrene (ABS) resins are effectively stabilized.Ethylenevinyl acetate copolymers are protected, as arebutene-methylacrylate copolymers. Nitrogen-containing polymers such aspolyurethanes, nitrile rubber, and lauryl acrylate-vinyl-pyrrolidonecopolymers are effectively stabilized. Adhesive compositions such assolutions of polychloroprene (neoprene) in toluene are protected.

Petroleum oils such as solvent-refined, midcontinent lubricating oil andGulfcoast lubricating oils are effectively stabilized. In hydrocarbonlubricating oils, both mineral and synthetic, the present additives areparticularly effective when used in combination with a zincdihydrocarbyldithiophosphate, e.g. zinc dialkyldithiophosphate or zincdialkaryldithiophosphate.

Synthetic ester lubricants such as those used in turbines and turbojetengines are given a high degree of stabilization. Typical syntheticester lubricants include di-2-ethylhexyl sebacate, trimethylolpropanetripelargonate, C₅₋₉ aliphatic monocarboxylic esters of pentaerythritol,complex esters formed by condensing under esterifying conditions,mixtures of polyols, polycarboxylic acids, and aliphatic monocarboxylicacids and/or monohydric alkanols. An example of these complex esters isthe condensation product formed from adipic acid, ethyleneglycol and amixture of C₅₋₉ aliphatic monocarboxylic acids. Plasticizers such asdioctyl phthalate are effectively protected. Heavy petroleum fractionssuch as tar and asphalt can also be protected should the need arise.

Polyamides such as adipic acid-1,6-diaminohexane condensates andpoly-6-aminohexanoic acid (nylon) are effectively stabilized.Polyalkylene oxides such as copolymers of phenol with ethylene oxide orpropylene oxide are stabilized. Polyphenyl ethers such aspoly-2,6-dimethylphenyl ether formed by polymerization of2,6-dimethylphenol using a copper-pyridine catalyst are stabilized.Polycarbonate plastics and other polyformaldehydes are also protected.

Linear polyesters such as phthalic anhydride-glycol condensates aregiven a high degree of protection. Polyesters such as those derived fromterephthalic acid and alkylene glycols are also given a high degree ofprotection. Other polyesters such as trimellitic acid-glycerolcondensates are also protected. Polyacrylates such as polymethylacrylateand polymethylmethacrylate are effectively stabilized.Polyacrylonitriles and copolymers of acrylonitriles with otherolefinically unsaturated monomers such as methylmethacrylates are alsoeffectively stabilized.

The additives can be used to protect any of the many organic substratesto which an antioxidant is normally added. It can be used whereeconomics permit to protect such substrates as asphalt, paper,fluorocarbons such as Teflon®, polyvinyl acetate, polyvinylidenechloride, coumarone-indene resins, polyvinyl ethers, polyvinylidenebromide, polyvinyl bromide, acrylonitrile, vinyl bromide copolymer,vinyl butyral resins, silicones such as dimethylsilicone lubricants,phosphate lubricants such as tricresylphosphate, and the like.

A preferred embodiment of the invention is the incorporation of theoxygen scavenger into polyethylene terephthalate formulations whichfurther include a transition metal catalyst. The oxygen scavenger worksparticularly well in the presence of the transition metal catalyst.

In combination with the polymer components, the oxygen scavengingcompositions including compounds of formula I or II of the presentinvention may include a transition metal salt, compound or complex, asan oxygen scavenger catalyst. The transition metal can be selected fromthe first, second, or third transition series of the Periodic Table. Themetal can be Rh, Ru, or one of the elements in the series of Sc to Zn(i.e., Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn). Suitable anions forthe salts include, but are not limited to, chloride, acetate, oleate,stearate, palmitate, 2-ethylhexanoate, neodecanoate, and naphthenate.Representative salts include cobalt (II) 2-ethylhexanoate, cobaltoleate, and cobalt (II) neodecanoate. The metal salt also can be anionomer, in which case a polymeric counter ion may be employed.

The amounts of the components used in the oxygen scavenging formulationsof the present invention can affect the use and effectiveness of thiscomposition. Thus, the amounts of polymer, transition metal catalyst,antioxidant, polymeric diluents, additives, etc., can vary depending onthe desired article and its end use. For example, one of the primaryfunctions of the polymers described above is to react irreversibly withoxygen during the scavenging process, while a primary function of thetransition metal catalyst is to facilitate this process. Thus, to alarge extent, the amount of polymer present affects the oxygenscavenging capacity of the composition, i.e., the amount of oxygen thatthe composition can consume, while the amount of transition metalcatalyst affects the rate at which oxygen is consumed as well as theinduction period.

Methods of incorporating the additive into the substrate are well known.For example, if the substrate is liquid the additive can be merely mixedinto the substrate. Frequently the organic substrate is in solution andthe additive is added to the solution and the solvent removed. Solidorganic substrates can be merely sprayed with a solution of the additivein a volatile solvent. For example, stabilized grain products resultfrom spraying the grain with a toluene solution of the additive. In thecase of rubbery polymers the additive can be added following thepolymerization stage by mixing it with the final emulsion or solutionpolymerization mixture and then coagulating or removing solvent torecover the stabilized polymer. It can also be added at the compoundingstage by merely mixing the additive with the rubbery polymer incommercial mixing equipment such as a Banbury blender. In this manner,rubbery polymers such as styrene-butadiene rubber, cispolybutadiene orisoprene polymers are blended with the antioxidant together with theother ingredients normally added such as carbon black, oil, sulfur, zincoxide, stearic acid, vulcanization accelerators, and the like. Followingmastication, the resultant mixture is fabricated and molded into afinished form and vulcanized.

The oxygen scavenger composition of the present invention can beincorporated in packaging articles having various forms. Suitablearticles include, but are not limited to, flexible sheet films, flexiblebags, pouches, semi-rigid and rigid containers such as bottles (e.g. PETbottles) or metal cans, or combinations thereof.

Typical flexible films and bags include those used to package variousfood items and may be made up of one or a multiplicity of layers to formthe overall film or bag-like packaging material. The oxygen scavengercomposition of the present invention can be used in one, some or all ofthe layers of such packaging material.

Typical rigid or semi-rigid articles include plastic, paper or cardboardcontainers, such as those utilized for juices, soft drinks, as well asthermoformed trays or cup normally having thickness in the range of from100 to 1000 micrometers. The walls of such articles can comprise singleor multiple layers of materials. The articles can also take the form ofa bottle or metal can, or a crown, cap, crown or cap liner, plastisol orgasket. The oxygen scavenger composition of the present invention can beused as an integral layer or portion of, or as an external or internalcoating or liner of, the formed semi-rigid or rigid packaging article.As a liner, the oxygen scavenger composition can be extruded as a filmalong with the rigid article itself, in e.g. a coextrusion, extrusioncoating, or extrusion lamination process, so as to form the liner insitu during article production; or alternatively can be adhered by heatand/or pressure, by adhesive, or by any other suitable method to anouter surface of the article after the article has been produced.

Although it may be preferable from the standpoint of packagingconvenience and/or scavenging effectiveness to employ the presentinvention as an integral or discrete part of the packaging wall, theinvention can also be used as a non-integral component of a packagingarticle such as, for example, a bottle cap liner, adhesive ornon-adhesive sheet insert, sealant, sachet, fibrous mat insert or thelike.

Besides articles applicable for packaging food and beverage, articlesfor packaging other oxygen-sensitive products can also benefit from thepresent invention. Such products would include pharmaceuticals, oxygensensitive medical products, corrodible metals or products, electronicdevices and the like.

In some embodiments of the invention, the base polymer in thecomposition is a polyester. In certain embodiments, the polyesterpolymers of the invention are thermoplastic and, thus, the form of thecompositions are not limited and can include a composition in the meltphase polymerization, as an amorphous pellet, as a solid stated polymer,as a semi-crystalline particle, as a composition of matter in a meltprocessing zone, as a bottle preform, or in the form of a stretch blowmolded bottle or other articles. In certain preferred embodiments, thepolyester is polyethylene terephthalate (PET).

Examples of suitable polyester polymers include polyethyleneterephthalate homopolymers and copolymers modified with one or morepolycarboxylic acid modifiers in a cumulative amount of less than about15 mole %, or about 10 mole % or less, or about 8 mole % or less, or oneor more hydroxyl compound modifiers in an amount of less than about 60mol %, or less than about 50 mole %, or less than about 40 mole %, orless than about 15 mole %, or about 10 mole % or less, or about 8 mole %or less (collectively referred to for brevity as “PET”) and polyethylenenaphthalate homopolymers and copolymers modified with a cumulativeamount of with less than about 15 mole %, or about 10 mole % or less, orabout 8 mole % or less, of one or more polycarboxylic acid modifiers ormodified less than about 60 mol %, or less than about 50 mole %, or lessthan about 40 mole %, or less than about 15 mole %, or about 10 mole %or less, or about 8 mole % or less of one or more hydroxyl compoundmodifiers (collectively referred to herein as “PEN”), and blends of PETand PEN. A modifier polycarboxylic acid compound or hydroxyl compound isa compound other than the compound contained in an amount of at leastabout 85 mole %. The preferred polyester polymer is polyalkyleneterephthalate, and most preferred is PET.

In some embodiments, the polyester polymer contains at least about 90mole % ethylene terephthalate repeat units, and in other embodiments, atleast about 92 mole %, and in yet other embodiments, or at least about94 mole %, based on the moles of all repeat units in the polyesterpolymers.

In addition to a diacid component of terephthalic acid, derivates ofterephthalic acid, naphthalene-2,6-dicarboxylic acid, derivatives ofnaphthalene-2,6-dicarboxylic acid, or mixtures thereof, thepolycarboxylic acid component(s) of the present polyester may includeone or more additional modifier polycarboxylic acids. Such additionalmodifier polycarboxylic acids include aromatic dicarboxylic acidspreferably having about 8 to about 14 carbon atoms, aliphaticdicarboxylic acids preferably having about 4 to about 12 carbon atoms,or cycloaliphatic dicarboxylic acids preferably having about 8 to about12 carbon atoms. Examples of modifier dicarboxylic acids useful as anacid component(s) are phthalic acid, isophthalic acid,naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid,cyclohexanediacetic acid, diphenyl-4,4′-dicarboxylic acid, succinicacid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and thelike, with isophthalic acid, naphthalene-2,6-dicarboxylic acid, andcyclohexanedicarboxylic acid being most preferable. It should beunderstood that use of the corresponding acid anhydrides, esters, andacid chlorides of these acids is included in the term “polycarboxylicacid.” It is also possible for trifunctional and higher orderpolycarboxylic acids to modify the polyester.

The hydroxyl component is made from compounds containing 2 or morehydroxyl groups capable of reacting with a carboxylic acid group. Insome preferred embodiments, preferred hydroxyl compounds contain 2 or 3hydroxyl groups. Certain preferred embodiments, have 2 hydroxyl groups.These hydroxyl compounds include C₂-C₄ alkane diols, such as ethyleneglycol, propane diol, and butane diol, among which ethylene glycol ismost preferred for container applications. In addition to these diols,other modifier hydroxyl compound component(s) may include diols such ascycloaliphatic diols preferably having 6 to 20 carbon atoms and/oraliphatic diols preferably having about 3 to about 20 carbon atoms.Examples of such diols include diethylene glycol; triethylene glycol;1,4-cyclohexanedimethanol; propane-1,3-diol and butane-1,4-diol (whichare considered modifier diols if ethylene glycol residues are present inthe polymer in an amount of at least 85 mole % based on the moles of allhydroxyl compound residues); pentane-1,5-diol; hexane-1,6-diol;3-methylpentanediol-(2,4); neopentyl glycol; 2-methylpentanediol-(1,4);2,2,4-trimethylpentane-diol-(1,3); 2,5-ethylhexanediol-(1,3);2,2-diethyl propane-diol-(1,3); hexanediol-(1,3);1,4-di-(hydroxyethoxy)-benzene; 2,2-bis-(4-hydroxycyclohexyl)-propane;2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane;2,2-bis-(3-hydroxyethoxyphenyl)-propane; and2,2-bis-(4-hydroxypropoxyphenyl)-propane. Typically, polyesters such aspolyethylene terephthalate are made by reacting a glycol with adicarboxylic acid as the free acid or its dimethyl ester to produce anester monomer and/or oligomers, which are then polycondensed to producethe polyester.

In some preferred embodiments, modifiers include isophthalic acid,naphthalenic dicarboxylic acid, trimellitic anhydride, pyromelliticdianhydride, 1,4-cyclohexane dimethanol, and diethylene glycol. Theamount of the polyester polymer in the formulated polyester polymercomposition ranges from greater than about 50.0 wt. %, or from about80.0 wt. %, or from about 90.0 wt. %, or from about 95.0 wt. %, or fromabout 96.0 wt. %, or from about 97 wt. %, and up to about 99.90 wt. %,based on the combined weight of all polyester polymers and all polyamidepolymers. The formulated polyester polymer compositions may also includeblends of formulated polyester polymer compositions with otherthermoplastic polymers such as polycarbonate. In some preferredcompositions, the polyester comprises a majority of the composition ofthe inventions, and in some embodiments the polyester is present in anamount of at least about 80 wt. %, or at least about 90 wt. %, based onthe weight of the composition (excluding fillers, inorganic compounds orparticles, fibers, impact modifiers, or other polymers serve as impactmodifiers or which form a discontinuous phase such as may be found incold storage food trays).

The polyester compositions can be prepared by polymerization proceduresknown in the art sufficient to effect esterification andpolycondensation. Polyester melt phase manufacturing processes includedirect condensation of a dicarboxylic acid with the diol, optionally inthe presence of esterification catalysts, in the esterification zone,followed by polycondensation in the prepolymer and finishing zones inthe presence of a polycondensation catalyst; or ester exchange usuallyin the presence of a transesterification catalyst in the ester exchangezone, followed by prepolymerization and finishing in the presence of apolycondensation catalyst, and each may optionally be solid statedaccording to known methods.

The transition metal used in the instant compositions is a metal in thepositive oxidation state. It should be noted that it is contemplatedthat one or more such metals may be used. In some embodiments, cobalt isadded in +2 or +3 oxidation state. In some embodiments, it is preferredto use cobalt in the +2 oxidation state. In certain embodiments, copperin the +2 oxidation state is utilized. In some embodiments, rhodium inthe +2 oxidation state is used. In certain embodiments, zinc may also beadded to the composition. Preferred zinc compounds include those in apositive oxidation state.

Suitable counter-ions to the transition metal cations includecarboxylates, such as neodecanoates, octanoates, acetates, lactates,naphthalates, malates, stearates, acetylacetonates, linoleates, oleates,palmitates, 2-ethylhexanoates, or ethylene glycolates; or as theiroxides, borates, carbonates, chlorides, dioxides, hydroxides, nitrates,phosphates, sulfates, or silicates among others.

In some embodiments, levels of at least about 10 ppm, or at least about50 ppm, or at least about 100 ppm of metal can achieve suitable oxygenscavenging levels. The exact amount of transition metal used in anapplication can be determined by trials that are well within the skilllevel of one skilled in the art. In some embodiments involving wallapplications (as opposed to master batch applications where morecatalyst is used), it is preferred to keep the level of metal belowabout 300 ppm and, in other embodiments, preferably below about 250 ppm.

The transition metal or metals may be added neat or in a carrier (suchas a liquid or wax) to an extruder or other device for making thearticle, or the metal may be present in a concentrate or carrier withthe oxidizable organic component, in a concentrate or carrier with abase polymer, or in a concentrate or carrier with a basepolymer/oxidizable organic component blend. Alternatively, at least aportion of the transition metal may be added as a polymerizationcatalyst to the melt phase reaction for making the base polymer (apolyester polymer in some embodiments) and be present as residual metalswhen the polymer is fed to the melting zone (e.g. the extrusion orinjection molding zone) for making the article such as a preform orsheet. It is desirable that the addition of the transition metal doesnot substantially increase the intrinsic viscosity (It.V) of the melt inthe melt processing zone. Thus, transition metal or metals may be addedin two or more stages, such as once during the melt phase for theproduction of the polyester polymer and again once more to the meltingzone for making the article.

The composition may also include other components such as pigments,fillers, crystallization aids, impact modifiers, surface lubricants,denesting agents, stabilizers, ultraviolet light absorbing agents, metaldeactivators, nucleating agents such as polyethylene and polypropylene,phosphate stabilizers and dyestuffs. Other additional components arewell known to those skilled in the art and can be added to the existingcomposition so long as they do not negatively impact the performance ofthe compositions. Typically, the total quantity of such components willbe less than about 10% by weight relative to the whole composition. Insome embodiments, the amount of these optional components is less thanabout 5%, by weight relative to the total composition.

A common additive used in the manufacture of polyester polymercompositions used to make stretch blow molded bottles is a reheatadditive because the preforms made from the composition must be reheatedprior to entering the mold for stretch blowing into a bottle. Any of theconventional reheat additives can be used, such additives includevarious forms of black particles, e.g. carbon black, activated carbon,black iron oxide, glassy carbon, and silicon carbide; the gray particlessuch as antimony, and other reheat additives such as silicas, red ironoxide, and so forth.

Other typical additives, depending on the application, are impactmodifiers. Examples of typical commercially available impact modifierswell-known in the art and useful in this invention includeethylene/acrylate/glycidyl terpolymers and ethylene/acrylate copolymersin which the acrylate is a methyl or ethyl acrylate or methyl or ethylmethacrylate or the corresponding butyl acrylates, styrene based blockcopolymers, and various acrylic core/shell type impact modifiers. Theimpact modifiers may be used in conventional amounts from about 0.1 toabout 25 weight percent of the overall composition and, in someembodiments, preferably in amounts from about 0.1 to about 10 weightpercent of the composition.

In many applications, not only are the packaging contents sensitive tothe ingress of oxygen, but the contents may also be affected by UVlight. Fruit juices and pharmaceuticals are two examples of suchcontents. Accordingly, in some embodiments, it is desirable toincorporate into the polyester composition any one of the known UVabsorbing compounds in amounts effective to protect the packagedcontents.

The instant compositions can be made by mixing a base polymer (PET, forexample) with the oxidizable organic component and the transition metalcomposition. Such compositions can be made by any method known to thoseskilled in the art. In certain embodiments, some or part of thetransition metal may exist in the base polymer prior to mixing. Thisresidual metal, for example, can exist from the manufacturing process ofthe base polymer. In some embodiments, the base polymer, the oxidizableorganic component and the transition metal are mixed by tumbling in ahopper. Other optional ingredients can be added during this mixingprocess or added to the mixture after the aforementioned mixing or to anindividual component prior to the aforementioned mixing step.

The instant composition can also be made by adding each ingredientseparately and mixing the ingredients prior melt processing thecomposition to form an article. In some embodiments, the mixing can bejust prior to the melt process zone. In other embodiments, one or moreingredients can be premixed in a separate step prior to bringing all ofthe ingredients together.

In some embodiments, the invention concerns use of the compositionsdescribed herein as a component of a wall that is used in a package foroxygen sensitive materials. The necessary scavenging capacity of apackage will generally have to be greater for walls that have a greaterpermeance in the absence of scavenging additives. Accordingly, a goodeffect is harder to achieve with inherently higher permeance materialsare used.

The wall may be a rigid one, a flexible sheet, or a clinging film. Itmay be homogenous or a laminate or coated with other polymers. If it islaminated or coated, then the scavenging property may reside in a layerof the wall the permeance of which is relatively high in the absence ofscavenging and which alone would not perform very satisfactorily butwhich performs satisfactorily in combination with one or more otherlayers which have a relatively low permeance but negligible orinsufficient oxygen-scavenging properties. A single such layer could beused on the outside of the package since this is the side from whichoxygen primarily comes when the package is filled and sealed. However,such a layer to either side of the scavenging layer would reduceconsumption of scavenging capacity prior to filling and sealing.

When the instant compositions are used in a wall or as a layer of awall, the permeability of the composition for oxygen is advantageouslynot more than about 3.0, or about 1.7, or about 0.7, or about 0.2, orabout 0.03 cm3 mm/(m² atm day). The permeability of the compositionprovided by the present invention is advantageously not more than aboutthree-quarters of that in the absence of oxygen-scavenging properties.In some embodiments, the permeability is not more than about one half,one-tenth in certain embodiments, one twenty-fifth in other embodiments,and not more than one-hundredth in yet other embodiments of that in theabsence of oxygen-scavenging properties. The permeability in the absenceof oxygen-scavenging properties is advantageously not more than about 17cm³ mm/(m² atm day), or about 10, and or about 6. A particularly goodeffect can be achieved for such permeabilities in the range from about0.5, or about 1.0, to 10, or about 6.0, cm³ mm/(m² atm day).Measurements of oxygen permeation can be made by methods described, forexample, in U.S. Pat. No. 5,639,815, the contents of which areincorporated herein in its entirety.

In another aspect, the instant composition can be used as a master batchfor blending with a polymer or a polymer containing component. In suchcompositions, the concentration of the oxidizable organic component andthe transition metal will be higher to allow for the final blendedproduct to have suitable amounts of these components. The master batchmay also contain an amount of the polymer to which the master batch isto be blended with. In other embodiments, the master batch may contain apolymer that is compatible with the polymer that the master batch is tobe blended with.

In yet another aspect, the compositions of the instant invention can beused for forming a layer of a wall which primarily providesoxygen-scavenging (another layer including polymer providing gas barrierwithout significant scavenging), or as a head-space scavenger(completely enclosed, together with the package contents, by a packagewall). Such techniques are well know to those skilled in the art.Persons familiar with oxygen scavenging technology and products willunderstand how to implement the structures disclosed in this paragraph.

The time period for which the permeability is maintained can be extendedby storing the articles in sealed containers or under an inertatmosphere such as nitrogen prior to use with oxygen sensitivematerials.

In another aspect, the invention provides a package, whether rigid,semi-rigid, collapsible, lidded, or flexible or a combination of these,comprising a wall as formed from the compositions described herein. Suchpackages can be formed by methods well known to those skilled in theart.

Among the techniques that may be used to make articles are mouldinggenerally, injection moulding, stretch blow moulding, extrusion,thermoforming, extrusion blow moulding, and (specifically for multilayerstructures) co-extrusion and lamination using adhesive tie layers.Orientation, e.g. by stretch blow moulding, of the polymer is especiallyattractive with phthalate polyesters because of the known mechanicaladvantages that result.

The melt processing zone for making the article can be operated undercustomary conditions effective for making the intended articles, such aspreforms, bottles, trays, and other articles mentioned below. In oneembodiment, such conditions are effective to process the melt withoutsubstantially increasing the It.V. of the melt and which are ineffectiveto promote transesterification reactions. In some preferred embodiments,suitable operating conditions effective to establish a physical blend ofthe polyester polymer, oxidizable organic component, and transitionmetal are temperatures in the melt processing zone within a range ofabout 250° C. to about 300° C. at a total cycle time of less than about6 minutes, and typically without the application of vacuum and under apositive pressure ranging from about 0 psig to about 900 psig. In someembodiments, the residence time of the melt on the screw can range fromabout 1 to about 4 minutes.

Specific articles include preforms, containers and films for packagingof food, beverages, cosmetics, pharmaceuticals, and personal careproducts where a high oxygen barrier is needed. Examples of beveragecontainers are bottles for holding water and carbonated soft drinks, andthe invention is particularly useful in bottle applications containingjuices, sport drinks, beer or any other beverage where oxygendetrimentally affects the flavor, fragrance, performance (preventvitamin degradation), or color of the drink. The compositions of theinstant invention are also particularly useful as a sheet forthermoforming into rigid packages and films for flexible structures.Rigid packages include food trays and lids. Examples of food trayapplications include dual ovenable food trays, or cold storage foodtrays, both in the base container and in the lidding (whether athermoformed lid or a film), where the freshness of the food contentscan decay with the ingress of oxygen. The compositions of the instantinvention also find use in the manufacture of cosmetic containers andcontainers for pharmaceuticals or medical devices.

The package walls of the instant invention can be a single layer or amultilayer constructions. In some embodiments using multilayer walls,the outer and inner layers may be structural layers with one or moreprotective layers containing the oxygen scavenging material positionedthere between. In some embodiments, the outer and inner layers compriseand polyolefin or a polyester. In certain embodiments, a single layerdesign is preferred. Such a layer may have advantages in simplicity ofmanufacture and cost.

Unless otherwise indicated, the invention is not limited to specificmolecular structures, substituents, synthetic methods, reactionconditions, or the like, as such may vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only and is not intended to be limiting.

In this specification and in the claims that follow, reference will bemade to a number of terms, which shall be defined to have the followingmeanings:

As used herein, the phrase “having the formula” or “having thestructure” is not intended to be limiting and is used in the same waythat the term “comprising” is commonly used. The term “independentlyselected from” is used herein to indicate that the recited elements,e.g., R groups or the like, can be identical or different.

As used herein, the terms “a”, “an”, “the” and the like refer to boththe singular and plural unless the context clearly indicates otherwise.“A bottle”, for example, refers to a single bottle or more than onebottle.

Also as used herein, the description of one or more method steps doesnot preclude the presence of additional method steps before or after thecombined recited steps. Additional steps may also be intervening stepsto those described. In addition, it is understood that the lettering ofprocess steps or ingredients is a convenient means for identifyingdiscrete activities or ingredients and the recited lettering can bearranged in any sequence.

Where a range of numbers is presented in the application, it isunderstood that the range includes all integers and fractions thereofbetween the stated range limits. A range of numbers expressly includesnumbers less than the stated endpoints and those in-between the statedrange. A range of from 1-3, for example, includes the integers one, two,and three as well as any fractions that reside between these integers.

As used herein, “master batch” refers to a mixture of base polymer,oxidizable organic component, and transition metal that will be diluted,typically with at least additional base polymer, prior to forming anarticle. As such, the concentrations of oxidizable organic component andtransition metal are higher than in the formed article.

The following examples are included to demonstrate preferred embodimentsof the invention regarding synthesis of the molecules and use of themolecules to scavenge oxygen as well products containing suchscavengers. It should be appreciated by those of skill in the art thatthe techniques disclosed in the examples which follow representtechniques discovered by the inventors to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

EXAMPLES Example 1

2 g of MXBP is placed in a 22 cc vial having an oxygen sensitive oxydoton the sidewall of the vial. The vial is sealed such that there is noexchange with the outside environment. A sealed, empty air vial was usedas control.

m-xylene bis-phthalimide (MXBP)

Initial percent oxygen levels in the vials are measured at roomtemperature (˜22° C.) using an Oxysense instrument (Oxysense, Inc., LasVegas, Nev.). The vials are then placed in an air-circulated oven at 75°C. After 1 day in the oven, the vials are removed, cooled to roomtemperature, and measured for percent oxygen levels. After measurementof 5 oxygen levels, the vials are returned to the 75° C. oven. Thisprocedure is repeated for 18 days. Data generated from thesemeasurements is shown in FIG. 1.

As seen in FIG. 1, MXBP scavenges approximately 4% of oxygen after 18days.

Example 2

PET resin (Vitiva™, Eastman Chemical Company, Kingsport, Tenn.) is driedin a Piovan Dryer (Model # DSN 520 HE, Piovan Canada, Mississauga,Ontario), at 170° C. for 4 hours (dew point of air used =−50° C.) priorto being fed to an injection molding machine. Moisture content of theresin (after 4 hrs/170° C.) is measured by a Mark 2 HP Moisture analyzer(Sartorious Omnimark Instrument Corp., Temp, Ariz.). The moisturecontent of the dried PET is approximately 33 ppm.

Cobalt containing polyester (Masterbatch) (4000 ppm Cobalt) is dried ina Dri Air Model RH 15 dryer (Dri-Air Industries, Inc., East Windsor,Conn.) at 291° F. for 3 hours.

A mixture of 2.5 wt % MXBP powder, 2 wt % Cobalt Masterbatch, and 95.5wt % Vitiva is blended in a bucket. The mixture is poured in the feedhopper of a Husky LX160 injection molding machine (two-cavity, 160tonnes clamping pressure, Husky Injection Molding Systems Ltd., Novi,Mich.) to produce preforms. The preforms made from this mixture are fora 16 oz. stock hot fill (36 gram preform weight) bottle. The preformsare blown into a bottle on a Sidel SBO 2/3 blow molding machine (SidelInc., Norcross, Ga.).

A portion of the Monomer MXBP bottle sidewall was analyzed for cobaltand nitrogen content at Gas Technology Institute, Des Plaines, Ill.Cobalt levels are determined to be approximately 67 ppm and the nitrogencontent is approximately 0.11 ppm. This corresponds to approximately1.45 weight percent of MXBP in the bottle wall.

Example 3 Preparation of QC (Reference)

A preform containing nylon MXD6 (1.5%, based on total weight ofpreform), cobalt masterbatch (2%, based of total weight of preform), inPET is prepared. The preform is then ground up and used as a controlduring oxygen scavenging testing.

Example 4

Approximately two weeks after being blown, six bottles preparedaccording to Example 2 are placed on an Illiop oxygen transmissionmeasuring machine (Constar International, Inc., Philadelphia, Pa.) tomeasure oxygen transmission rate. The steady state oxygen permeationrate for all the bottles was found to be approximately 0.0005 cc/pkg/day(see Table 1).

TABLE 1 Bottle No. 15 17 18 19 20 21 Equilibrium 0.0005 0.0007 0.00040.0004 0.0004 0.0005 Transmission Rate (mL/pkg/day)

Example 5

PET resin (Vitiva™, Eastman Chemical Company, Kingsport, Tenn.) is driedin a Nissei dryer at 170° C. for 4 hours prior to use. Cobalt containingpolyester (Masterbatch) (4000 ppm Cobalt) is dried for approximately 2hours at 350° F. prior to use.

Plaques (approximately 33.5 gram weight) are molded on 30-ton BOY 22Sinjection molding machine using the following settings:

Barrel temperature 264° C. Nozzle heater setting 35% of the power usedto heat the barrel Sprue heater set temperature approx. 215° C.Injection pressure 600 psi (20 sec. of hold pressure; 15 sec. moldcooling time)

The mold is water cooled with process water flow rate at approximately0.5 LPM.

MXBP powder (25.09 g) is hand blended in a bucket with dried Masterbatch(20.09 g) and dried PET (958.4 g). This mixture is poured in the feedhopper of the BOY 22S machine.

The first 10 plaques are discarded as change-over plaques. After thefirst 10 plaques are discarded, 8 plaques are collected for oxygenscavenging evaluation. Data generated from oxygen scavenging evaluationis shown in FIG. 2.

As seen in FIG. 2, PET plaques containing MXBP scavenge approximately14% of oxygen after 25 days.

Example 6 Preparation of MXBP

m-xylene bis-phthalimide (MXBP)

To phthalide 674.1 g. (5.026 mol) heated to 115° C. was addedm-xylylenediamine 325.9 g (2.393 mol) with nitrogen sparge. The solutionwas heated to 190° C. and held for 1.5 hours during which time 20 mL ofwater distillate was collected in a Dean-Stark trap. The heat was thenincreased to 200° C. and held for 3.5 hours during which time anadditional 23 mL of water was collected. The heat was then was increasedto 210° C. and held for 12 hours during which time an additional 15 mLof water was collected. The amine value by titration with 0.1 Nperchloric acid in glacial acetic acid was 28.1 mg KOH/gram of sample.Reaction was held an additional 7 hours at 215° C. during which time anadditional 2 mL of water was collected and the amine value had droppedto 18.1 mg KOH/gram of sample. This solution was cooled to 125° C. and1-methyl-2-pyrrolidinone 500 grams was added. The solution was cooled to90° C. and poured into water 4 L containing glacial acetic acid 40 gwith mixing to create a slurry. This was filtered to yield 1000 g ofpress cake. This was added to isopropanol (IPA) 1000 g and water 2000 gand the resulting slurry was filtered to yield 1000 g of press cake.This was added to IPA 2200 g and the resulting slurry was filtered toyield 1600 g of press cake. This was added to IPA 1500 g and theresulting slurry was filtered to yield 1350 g of press cake. This wasadded to IPA 1300 g and the resulting slurry was filtered to yield 1240g of press cake. This was dried at 60° C. to yield 671 g (73.4% yield)of product. Its melting point was 154-157° C. The amine value was lessthan 0.5 mg KOH/gram of sample. The infrared spectra was consistent withthe desired product.

Example 7 Alternative Preparation of MXBP

To phthalide 505.6 g (3.769 mol) heated to 115° C. was addedm-xylylenediamine 244.4 g (1.795 mol) with nitrogen sparge. The solutionwas heated to 180° C. and held for 3.5 hours during which time 14 mL ofwater distillate was collected in a Dean-Stark trap. The heat was thenincreased to 190° C. and held for 20 hours during which time anadditional 15 mL of water was collected. The amine value was 47 mgKOH/gram of sample. The heat was then increased to 205° C. and held for7 hours during which time an additional 22 mL of water was collected.The amine value was 30 mg KOH/gram of sample. The heat was thenincreased to 210° C. and held for 15 hours during which time anadditional 5 mL of water was collected. The amine value was 11.7 mgKOH/gram of sample. The solution was cooled to 185° C. and cast into analuminum tray to yield 661.7 g of a clear, amber solid. This waspurified as shown in the following examples.

Example 8 Purification Methods for MXBP

Method A

To IPA 450 g and 1-methyl-2-pyrrolidinone 180 g was added the product ofExample 6 330 g and the mixture was heated to 90° C. to produce a clearsolution. This was poured into water 2000 mL and IPA 500 g to create aslurry. This was filtered and washed with IPA 300 g to yield 495 g ofpress cake. This was added to IPA 2500 g and filtered to yield 495 gpress cake. This was added to IPA 1500 g and filtered to yield 455 g ofpress cake. This was dried at 60° C. to yield 219 g (66.4% yield) of thedesired product.

Method B

To xylene 247 g was added the product of Example 6 165 g and the mixturewas heated to 140° C. to produce a clear solution. The solution wascooled to 50° C. and xylene 100 g was added. The resulting slurry wascooled to 30° C. This was filtered and washed with xylene 200 g to yield203 g of press cake. This was added to IPA 800 g and heated to 80° C. toproduce a clear solution. The solution was cooled to 36° C. and IPA 200g was added. The resulting slurry was cooled to 30° C. and held 0.5hours. This was filtered and washed with IPA 200 g to yield 232 g ofpress cake. This was air dried at ambient temperature to yield 110 g(66.7% yield) of the desired product.

Method C

To IPA 700 g was added the product of Example 6 140 g and the mixturewas heated to 80° C. to produce a clear solution. The solution wascooled to 32° C. and IPA 200 g was added. The resulting slurry wascooled to 30° C. and held 0.5 hours. This was filtered and washed withIPA 200 g to yield 220 g press cake. This was added to IPA 600 g andheated to 80° C. to produce a clear solution. This was cooled to 39° C.and IPA 200 g was added. The resulting slurry was cooled to 30° C. andheld 0.5 hours. This was filtered and washed with IPA 200 g to yield 232g of press cake. This was air dried at ambient temperature to yield 105g (75.0% yield) of the desired product.

Example 9

To a solution of 1-methyl-2-pyrrolidinone 280 g, xylene 420 g andphthalic anhydride 487.2 g (3.289 mol) heated to 120° C. was addedm-xylylenediamine 213.3 g (1.566 mol) over 10 minutes during which timethe temperature increased to 145° C. The solution was held at 140° C.for 1 hours during which time 55.0 mL of water distillate was collectedin a Dean-Stark trap. The solution was heated to 150° C. during whichtime an additional 5.0 mL of water was collected and the amine value was1.4 mg KOH/gram of sample. The resulting slurry was poured into analuminum tray. The cooled product was added to IPA 1000 g and theresulting slurry was filtered and washed with IPA 200 g. The press cakewas added to IPA 1000 g and the resulting slurry was filtered and washedwith IPA 200 g. The press cake was air dried at ambient temperature toyield 601.1 g (97.0% yield) of the desired product. Its melting pointwas 243-248° C. The infrared spectra was consistent with the desiredproduct.

Example 10 Compound 306

Step 1: Methyl-(2,5-dimethyl)benzoate

Into a suspension of 75 g (499 mmol) 2,5-dimethylbenzoic acid, 103 g(748 mmol) potassium carbonate in 500 mL of DMF was added dropwise 77.9g (549 mmol) of iodomethane with stirring at ambient temperature. Afteraddition, the suspension was stirred for additional 5 hours. Thereaction mixture was then poured into water and extracted with ethylacetate. The organic layer was washed with water and brine and driedover anhydrous sodium sulfate. All solids were removed by filtration andthe filtrate was concentrated to 80 g of colorless oil as product in97.6% yield. ¹H NMR (CDCl₃) (300 MHz) δ 2.7 (s, 3H), 2.8 (s, 3H), 3.95(s, 3H), 7.45 (s 1H), 7.51 (d, ³JHCCH=7.9 Hz, 1H), 7.42 (d, ³JHCCH=7.9Hz, 1H)

Step 2: Methyl-di(2,5-bromomethyl)benzoate

Into a mixture of 80 g (487 mmol) of methyl-(2,5-dimethyl)nitrobenzoate,95.4 g (503 mmol) of N-bromosuccinimide in 500 mL of carbontetrachloride was added 121 mg (0.5 mmol) of benzoyl peroxide at 80° C.Heating continued for 16 hours and cooled to ambient temperature. Thereaction mixture was then washed with saturated sodium bicarbonate andbrine. The organic layer was dried over anhydrous sodium sulfate. Allsolids were removed by filtration and the filtrate was concentrated to atotal of 152 g yellowish solid in 96.9% yield. ¹H NMR (CDCl₃) (300 MHz)δ 3.95 (s, 3H), 4.49 (s, 2H), 4.96 (s, 2H), 7.49 (s 1H), 7.54 (d,³JHCCH=7.9 Hz, 1H), 7.47 (d, ³JHCCH=7.9 Hz, 1H).

Step 3: 6-bromomethylphthalide

A neat sample of 152 g (472 mmol) of methyl-di(2,5-bromomethyl)benzoatewas heated to 120° C. in a slight vacuum. The yellowish solid melted at80° C. After 16 hours of heating, the reaction mixture was cooled toambient temperature. Upon cooling, a total of 107 g light brown solidwas obtained as product in quantitative yield. ¹H NMR (CDCl₃) (300 MHz)δ 4.58 (s, 2H), 5.30 (s, 2H), 7.49 (s 1H), 7.54 (d, ³JHCCH=7.9 Hz, 1H),7.47 (d, ³JHCCH=7.9 Hz, 1H)

Step 4: 6-methylphthalide

A total of 107 g (472 mmol) of 6-bromomethylphthalide was dissolved in50 mL of methanol (dioxane was also used in different experiment). Thesolution was added to a parr bottle with 40 g (540 mmol) of calciumhydroxide and 2 g of 10% Pd/C. The suspension was hydrogenated at 40 psiuntil no more hydrogen uptake was recorded. All solids were filtered andfiltrate was concentrated to a total of 67 g of brown solid in 96%yield. ¹H NMR (CDCl₃) (300 MHz) δ 2.53 (s, 3H), 5.30 (s, 2H), 7.49 (s1H), 7.54 (d, ³JHCCH=7.9 Hz, 1H), 7.47 (d, ³JHCCH=7.9 Hz, 1H)

Step 5: 1,3-Bis[(6-methyl-2,3-dihyro-isoindol-1-one-2-yl)methyl]benzene

A mixture of 67 g (452 mmol) 6-methylphthalide and 30.7 g (226 mmol)xylyldiamine was heated to 180° C. with a short path distillation setupto remove water. Upon 170°-180° C., water was collected. After 16 hoursof heating at 180° C., heating was stopped and reaction mixture wasdissolved in 200 mL of dimethylforamide. The DMF solution was then addeddropwise with stirring into 1.5 L of water to precipitate out a total of73 g of brownish solid. The solid was then recrystallized with methanolto give 55 g of product in 61% yield. ¹H NMR(DMSO-d⁶)(500 MHz) δ 2.54(s, 6H), 4.29 (s, 4H), 4.79 (s, 4H), 7.20 (dd, ³JHCCCH=7.6 Hz,⁴JHCCCH=1.4 Hz, 2H), 7.28 (dd, ³JHCCH=7.6 Hz, 1H), 7.30 (s, 1H) 7.66(dd, ⁴JHCCCH=1.4 Hz, ⁵JHCCCH=0.65 Hz, 2H), 7.56 (dd, ³JHCCCH=7.9 Hz,⁴JHCCCH=0.65 Hz, 2H), 7.60 (dd, ³JHCCCH=7.9 Hz, ⁴JHCCCH=1.4 Hz, 2H).

Preparation of Plaques

PET resin (Vitiva™, Eastman Chemical Company, Kingsport, Tenn.) is driedin a Nissei dryer at 170° C. for 4 hours prior to use. Cobalt containingpolyester (Masterbatch) (4000 ppm Cobalt) is dried for approximately 2hours at 350° F. prior to use.

Plaques (approximately 33.5 gram weight) are molded on 30-ton BOY 22Sinjection molding machine using the following settings:

Barrel temperature 264° C. Nozzle heater setting 35% of the power usedto heat the barrel Sprue heater set temperature approx. 215° C.Injection pressure 600 psi (20 sec. of hold pressure; 15 sec. moldcooling time)

The mold is water cooled with process water flow rate at approximately0.5 LPM.

Compound 306 (19 g) is hand blended in a bucket with dried Masterbatch(19 g) and dried PET (912 g). This mixture is poured in the feed hopperof the BOY 22S machine.

The first 10 plaques are discarded as change-over plaques. After thefirst 10 plaques are discarded, 8 plaques are collected for oxygenscavenging evaluation. Data generated from oxygen scavenging evaluationis shown in FIG. 3.

As seen in FIG. 3, PET plaques containing Compound 306 scavengeapproximately 3.9% of oxygen after 5.5 days.

Example 11 Compound 307 1,3-Bis[(isoindole-1,3-dione-2-yl)methyl]benzene

Into a suspension of 100 g (675 mmol) of phthalic anhydride, 46 g (338mmol) of xylyldiamine and 500 mL of glacial acetic acid was heated to100° C. After 2 hours of heating, the reaction mixture was a clearsolution. Heating continued for additional 22 hours. Upon cooling, whitesuspension was observed. The white solid was filtered and recrystallizedwith acetic acid to give 126.6 g of a white product in 94.5% yield. 1HNMR(DMSO-d₆)(500 MHz) δ 4.74 (s, 4H), 7.19 (dd, ³JHCCCH=7.7 Hz,⁴JHCCCH=1.5 Hz, 2H), 7.23 (s, 1H), 7.28 (dd, ³JHCCCH=7.7 Hz,1H), 7.86(unresolved complex, 8H).

Preparation of Plaques

PET resin (Vitiva™, Eastman Chemical Company, Kingsport, Tenn.) is driedin a Nissei dryer at 170° C. for 4 hours prior to use. Cobalt containingpolyester (Masterbatch) (4000 ppm Cobalt) is dried for approximately 2hours at 350° F. prior to use.

Plaques (approximately 33.5 gram weight) are molded on 30-ton BOY 22Sinjection molding machine using the following settings:

Barrel temperature 264° C. Nozzle heater setting 35% of the power usedto heat the barrel Sprue heater set temperature approx. 215° C.Injection pressure 600 psi (20 sec. of hold pressure; 15 sec. moldcooling time)

The mold is water cooled with process water flow rate at approximately0.5 LPM.

Compound 307 (38 g) is hand blended in a bucket with dried Masterbatch(19 g) and dried PET (893 g). This mixture is poured in the feed hopperof the BOY 22S machine.

The first 10 plaques are discarded as change-over plaques. After thefirst 10 plaques are discarded, 8 plaques are collected for oxygenscavenging evaluation. Data generated from oxygen scavenging evaluationis shown in FIG. 5.

As seen in FIG. 5, PET plaques containing Compound 307 scavengeapproximately 4% of oxygen after 25 days.

Example 12 Compound 310

Step 1: Methyl-(2-methyl-6-nitro)benzoate

Into a suspension of 100 g (552 mmol) of 2-methyl-6-nitrobenzoic acid,114.4 g (828 mmol) of potassium carbonate in 500 mL of dimethylforamidewas added dropwise 86 g (606 mmol) of iodomethane with stirring atambient temperature. After addition, the suspension was stirred foradditional 5 hours. The reaction mixture was then poured into water andextracted with ethyl acetate. The organic layer was washed with waterand brine and dried over anhydrous sodium sulfate. Any solid was removedby filtration and the filtrate was concentrated to a 105.6 g ofcolorless oil as product in 98% yield. ¹H NMR (CDCl₃) (300 MHz) δ 2.7(s, 3H), 3.95 (s, 3H), 8.01 (d, ³JHCCH=8.6 Hz, 1H), 7.62 (dd, ³JHCCH=8.6Hz, ³JHCCH=7.6 Hz, 1H), 7.8 (d, ³JHCCH=7.6 Hz, 1H)

Step 2: Methyl-(2-bromomethyl-6-nitro)benzoate

Into a mixture of 100 g (512 mmol) of methyl-(2-methyl-6-nitro)benzoate,100.2 g (563 mmol) of N-bromosuccinimide in 500 mL of carbontetrachloride was added 121 mg (0.5 mmol) of benzoyl peroxide at 80° C.Heating continued for 16 hours and cooled to ambient temperature. Thereaction mixture was then washed with saturated sodium bicarbonate andbrine. The organic layer was dried over anhydrous sodium sulfate. Allsolids were removed by filtration and the filtrate was concentrated to atotal of 137.5 g of yellowish oil in 98% yield. ¹H NMR (CDCl₃) (300 MHz)δ 3.95 (s, 3H), 4.96 (s, 2H) 8.01 (d, ³JHCCH=8.6 Hz), 7.62 (dd,³JHCCH=8.6 Hz, ³JHCCH=7.6 Hz), 7.85 (d, ³JHCCH=7.6 Hz)

Step 3: 1,3-Bis[(7-nitro-2,3-dihyro-isoindol-1-one-2-yl)methyl]benzene

Into a solution of 80 g (292 mmol) ofmethyl-(2-bromomethyl-6-nitro)benzoate, 19.9 g (146 mmol) ofXylyldiamine, 32.4 g (320 mmol) triethylamine and 300 mL of methanol washeated to reflux for 24 hours. Upon cooling, the mixture was dilutedwith ethyl acetate and washed with diluted hydrochloric acid and brine.The organic layer was dried over anhydrous sodium sulfate. All solidswere removed by filtration and filtrate was concentrated to 61 g of ayellowish solid. Methanol was used to recrystallize the yellowish solidto yield a total of 87 g of product in 65% yield. ¹H NMR(DMSO-d₆) (500MHz) δ 4.47 (s, 4H), 4.72 (s, 4H), 7.22 (dd, ³JHCCCH=7.5 Hz, ⁴JHCCCH=1.6Hz, 2H), 7.26 (s, 1H), 7.36 (dd, ³JHCCCH=7.5 Hz, 1H), 7.79 (dd,³JHCCCH=7.6 Hz, ³JHCCCH=7.6 Hz, 2H), 7.84 (dd, ³JHCCCH=7.6 Hz,⁴JHCCCH=1.0 Hz, 2H), 7.89 (dd, ³JHCCCH=7.6 Hz, ⁴JHCCCH=1.0 Hz, 2H).

Preparation of Plaques

PET resin (Vitiva™, Eastman Chemical Company, Kingsport, Tenn.) is driedin a Nissei dryer at 170° C. for 4 hours prior to use. Cobalt containingpolyester (Masterbatch) (4000 ppm Cobalt) is dried for approximately 2hours at 350° F. prior to use.

Plaques (approximately 33.5 gram weight) are molded on 30-ton BOY 22Sinjection molding machine using the following settings:

Barrel temperature 264° C. Nozzle heater setting 35% of the power usedto heat the barrel Sprue heater set temperature approx. 215° C.Injection pressure 600 psi (20 sec. of hold pressure; 15 sec. moldcooling time)

The mold is water cooled with process water flow rate at approximately0.5 LPM.

Compound 310 (23.8 g) is hand blended in a bucket with dried Masterbatch(19 g) and dried PET (908 g). This mixture is poured in the feed hopperof the BOY 22S machine.

The first 10 plaques are discarded as change-over plaques. After thefirst 10 plaques are discarded, 8 plaques are collected for oxygenscavenging evaluation. Data generated from oxygen scavenging evaluationis shown in FIG. 4.

As seen in FIG. 4, PET plaques containing Compound 310 scavengeapproximately 5% of oxygen after 25 days.

As those skilled in the art will appreciate, numerous modifications andvariations of the present invention are possible in light of the aboveteachings. It is therefore understood that within the scope of theappended claims, the invention may be practiced otherwise than asspecifically described herein, and the scope of the invention isintended to encompass all such variations.

1. A composition comprising: (a) a base polymer; (b) at least onecompound of formula

and (c) at least one transition metal in a positive oxidation state,said metal being present in the composition in an amount of 10 to 400ppm; wherein said compound is present in an amount of about 0.10 to 10weight percent of said composition.
 2. The composition of claim 1,wherein said at least one transition metal is cobalt.
 3. The compositionof claim 2 wherein said at least one transition metal further compriseszinc.
 4. The composition of claim 1 wherein said base polymer comprisesa polyester polymer.
 5. The composition of claim 4 wherein the polyesterpolymer is polyethylene terephthalate.
 6. The composition of claim 1wherein the compound is present in an amount of about 1 to about 10weight percent based on the weight of the composition.
 7. Thecomposition of claim 1 wherein the compound is present in an amount ofabout 1 to about 5 weight percent based on the weight of thecomposition.
 8. The composition of claim 1 wherein the compound ispresent in an amount of about 1 to about 3 weight percent based on theweight of the composition.
 9. The composition of claim 1 wherein theconcentration of transition metal is 30 to 150 ppm.
 10. The compositionof claim 1, wherein the compound is


11. A wall of a package comprising at least one layer, said layercomprising a composition, said composition comprising: (a) a basepolymer; (b) at least one compound of formula

and (c) at least one transition metal in a positive oxidation state,said metal being present in the composition in an amount of 10 to 400ppm; wherein said compound is present in an amount of about 0.10 to 10weight percent of said composition.
 12. The wall of claim 11 whereinsaid at least one transition metal comprises cobalt.
 13. The wall ofclaim 12 wherein said at least one transition metal further compriseszinc.
 14. The wall of claim 11 wherein said base polymer comprises apolyester polymer.
 15. The wall of claim 14 wherein the polyesterpolymer is polyethylene terephthalate.
 16. The wall of claim 11 whereinthe compound is present in an amount of about 1 to about 10 weightpercent based on the weight of the composition.
 17. The wall of claim 11wherein the compound is present in an amount of about 1 to about 5weight percent based on the weight of the composition.
 18. The wall ofclaim 11 wherein the compound is present in an amount of about 1 toabout 3 weight percent based on the weight of the composition.
 19. Thewall of claim 11 wherein the concentration of transition metal is 30 to150 ppm.
 20. The wall of claim 11, wherein the compound is


21. A method for packaging an oxygen sensitive material comprising: (a)preparing a package having a wall comprising at least one layer, atleast one of said layers comprising a composition, said compositioncomprising a base polymer; at least one compound of formula

and at least one transition metal in a positive oxidation state, saidmetal being present in the composition in an amount of 10 to 400 ppm;wherein said compound is present in an amount of about 0.10 to 10 weightpercent of said composition; (b) introducing said oxygen sensitivematerial into said package; and (c) closing said package.
 22. The methodof claim 21 wherein said at least one transition metal comprises cobalt.23. The method of claim 22 wherein said at least one transition metalfurther comprises zinc.
 24. The method of claim 21 wherein said basepolymer comprises a polyester polymer.
 25. The method of claim 24wherein the polyester polymer is polyethylene terephthalate.
 26. Themethod of claim 21 wherein the compound is present in an amount of about1 to about 10 weight percent based on the weight of the composition. 27.The method of claim 21 wherein the compound is present in an amount ofabout 1 to about 5 weight percent based on the weight of thecomposition.
 28. The method of claim 21 wherein the compound is presentin an amount of about 1 to about 3 weight percent based on the weight ofthe composition.
 29. The method of claim 21 wherein the concentration oftransition metal is 30 to 150 ppm.
 30. The method of claim 21, whereinthe compound is


31. A process for making an article comprising: (a) forming a melt bycombining in a melt processing zone: a base polymer, at least onecompound of formula

and at least one transition metal in a positive oxidation state, saidmetal being present in the composition in an amount of 10 to 400 ppm;wherein the compound is present in an amount of about 0.10 to 10 weightpresent of said composition; (b) forming an article from said melt. 32.The process of claim 31 wherein said at least one transition metalcomprises cobalt.
 33. The process of claim 32 wherein said at least onetransition metal further comprises zinc.
 34. The process of claim 31wherein said base polymer comprises a polyester polymer.
 35. The processof claim 34 wherein the polyester polymer is polyethylene terephthalate.36. The process of claim 31 wherein the compound is present in an amountof about 1 to about 10 weight percent based on the weight of thecomposition.
 37. The process of claim 31 wherein the compound is presentin an amount of about 1 to about 5 weight percent based on the weight ofthe composition.
 38. The process of claim 31 wherein the compound ispresent in an amount of about 1 to about 3 weight percent based on theweight of the composition.
 39. The process of claim 31 wherein theconcentration of transition metal is 30 to 150 ppm.
 40. The process ofclaim 31 wherein the article is a preform.
 41. The process of claim 31wherein the article is a sheet.
 42. The process of claim 41 wherein thearticle is a bottle, a cup, or a jar.
 43. The process of claim 31,wherein the compound is


44. A container from a film-forming polymer, having at least one wallcomprising an effective amount of an oxygen-scavenging compositioncomprising a compound of formula


45. The container of claim 44, wherein the compound is